exo: Implement zcr_linux_explicit_synchronization_v1

components/exo/buffer.cc

Index: components/exo/buffer.cc
diff --git a/components/exo/buffer.cc b/components/exo/buffer.cc
index 0c771df3d66a9af9af0a44c9fa7e7f412b238e52..3e2486a5ff90628eed325a41315e51e5987dbcab 100644
--- a/components/exo/buffer.cc
+++ b/components/exo/buffer.cc
@@ -28,6 +28,7 @@
 #include "gpu/command_buffer/client/gles2_interface.h"
 #include "ui/aura/env.h"
 #include "ui/compositor/compositor.h"
+#include "ui/gfx/gpu_fence.h"
 #include "ui/gfx/gpu_memory_buffer.h"
 
 namespace exo {
@@ -118,7 +119,7 @@ class Buffer::Texture : public ui::ContextFactoryObserver {
   // Binds the contents referenced by |image_id_| to the texture returned by
   // mailbox(). Returns a sync token that can be used when accessing texture
   // from a different context.
-  gpu::SyncToken BindTexImage();
+  gpu::SyncToken BindTexImage(gfx::GpuFence* acquire_fence);

[reveman, 2016/10/12 19:20:19]

nit: sometimes "acquire_fence" name is used and sometimes just "fence", can we
make this consistent throughout this file and just use "fence"?

 
   // Releases the contents referenced by |image_id_| after |sync_token| has
   // passed and runs |callback| when completed.
@@ -129,7 +130,8 @@ class Buffer::Texture : public ui::ContextFactoryObserver {
   // Copy the contents of texture to |destination| and runs |callback| when
   // completed. Returns a sync token that can be used when accessing texture
   // from a different context.
-  gpu::SyncToken CopyTexImage(Texture* destination,
+  gpu::SyncToken CopyTexImage(gfx::GpuFence* acquire_fence,
+                              Texture* destination,
                               const base::Closure& callback);
 
   // Returns the mailbox for this texture.
@@ -150,6 +152,7 @@ class Buffer::Texture : public ui::ContextFactoryObserver {
   unsigned image_id_ = 0;
   unsigned query_id_ = 0;
   unsigned texture_id_ = 0;
+  unsigned fence_id_ = 0;
   gpu::Mailbox mailbox_;
   base::Closure release_callback_;
   base::TimeTicks wait_for_release_time_;
@@ -231,14 +234,18 @@ void Buffer::Texture::Release(const base::Closure& callback,
   callback.Run();
 }
 
-gpu::SyncToken Buffer::Texture::BindTexImage() {
+gpu::SyncToken Buffer::Texture::BindTexImage(gfx::GpuFence* acquire_fence) {
   gpu::SyncToken sync_token;
   if (context_provider_) {
     gpu::gles2::GLES2Interface* gles2 = context_provider_->ContextGL();
     gles2->ActiveTexture(GL_TEXTURE0);
     gles2->BindTexture(texture_target_, texture_id_);
     DCHECK_NE(image_id_, 0u);
-    gles2->BindTexImage2DCHROMIUM(texture_target_, image_id_, 0);
+    if (acquire_fence) {
+      fence_id_ = gles2->CreateFenceCHROMIUM(acquire_fence->AsClientFence());
+      DCHECK_NE(fence_id_, 0u);
+    }
+    gles2->BindTexImage2DCHROMIUM(texture_target_, image_id_, fence_id_);
     // Generate a crypto-secure random mailbox name if not already done.
     if (mailbox_.IsZero())
       CreateGLTextureMailbox(gles2, texture_id_, texture_target_, &mailbox_);
@@ -264,6 +271,8 @@ void Buffer::Texture::ReleaseTexImage(const base::Closure& callback,
     DCHECK_NE(query_id_, 0u);
     gles2->BeginQueryEXT(query_type_, query_id_);
     gles2->ReleaseTexImage2DCHROMIUM(texture_target_, image_id_);
+    if (fence_id_ != 0u)

[reveman, 2016/10/12 19:20:19]

nit: "if (fence_id_)" is preferred in chromium code

+      gles2->DestroyFenceCHROMIUM(fence_id_);
     gles2->EndQueryEXT(query_type_);
     // Run callback when query result is available and ReleaseTexImage has been
     // handled if sync token has data and buffer has been used. If buffer was
@@ -276,7 +285,8 @@ void Buffer::Texture::ReleaseTexImage(const base::Closure& callback,
   callback.Run();
 }
 
-gpu::SyncToken Buffer::Texture::CopyTexImage(Texture* destination,
+gpu::SyncToken Buffer::Texture::CopyTexImage(gfx::GpuFence* acquire_fence,
+                                             Texture* destination,
                                              const base::Closure& callback) {
   gpu::SyncToken sync_token;
   if (context_provider_) {
@@ -284,13 +294,19 @@ gpu::SyncToken Buffer::Texture::CopyTexImage(Texture* destination,
     gles2->ActiveTexture(GL_TEXTURE0);
     gles2->BindTexture(texture_target_, texture_id_);
     DCHECK_NE(image_id_, 0u);
-    gles2->BindTexImage2DCHROMIUM(texture_target_, image_id_, 0);
+    if (acquire_fence) {
+      fence_id_ = gles2->CreateFenceCHROMIUM(acquire_fence->AsClientFence());
+      DCHECK_NE(fence_id_, 0u);
+    }
+    gles2->BindTexImage2DCHROMIUM(texture_target_, image_id_, fence_id_);
     gles2->CopyTextureCHROMIUM(texture_id_, destination->texture_id_,
                                internalformat_, GL_UNSIGNED_BYTE, false, false,
                                false);
     DCHECK_NE(query_id_, 0u);
     gles2->BeginQueryEXT(query_type_, query_id_);
     gles2->ReleaseTexImage2DCHROMIUM(texture_target_, image_id_);
+    if (fence_id_ != 0u)

[reveman, 2016/10/12 19:20:18]

nit: "if (fence_id_)" is preferred in chromium code

+      gles2->DestroyFenceCHROMIUM(fence_id_);

[reveman, 2016/10/12 19:20:19]

nit: set fence_id_ to 0 here so it's easier to tell if we use it after
destruction by mistake

     gles2->EndQueryEXT(query_type_);
     // Run callback when query result is available and ReleaseTexImage has been
     // handled.
@@ -400,6 +416,7 @@ Buffer::~Buffer() {}
 
 std::unique_ptr<cc::SingleReleaseCallback> Buffer::ProduceTextureMailbox(
     cc::TextureMailbox* texture_mailbox,
+    gfx::GpuFence* acquire_fence,

[reveman, 2016/10/12 19:20:19]

nit: s/acquire_fence/fence/ to be consistent with declaration in .h file

     bool secure_output_only,
     bool client_usage) {
   DCHECK(attach_count_);
@@ -450,7 +467,7 @@ std::unique_ptr<cc::SingleReleaseCallback> Buffer::ProduceTextureMailbox(
     Texture* texture = contents_texture_.get();
 
     // This binds the latest contents of this buffer to |texture|.
-    gpu::SyncToken sync_token = texture->BindTexImage();
+    gpu::SyncToken sync_token = texture->BindTexImage(std::move(acquire_fence));
 
     *texture_mailbox =
         cc::TextureMailbox(texture->mailbox(), sync_token, texture_target_,
@@ -476,7 +493,7 @@ std::unique_ptr<cc::SingleReleaseCallback> Buffer::ProduceTextureMailbox(
   Texture* texture = texture_.get();
 
   // The contents texture will be released when copy has completed.
-  gpu::SyncToken sync_token = contents_texture->CopyTexImage(
+  gpu::SyncToken sync_token = contents_texture->CopyTexImage(std::move(acquire_fence),
       texture, base::Bind(&Buffer::ReleaseContentsTexture, AsWeakPtr(),
                           base::Passed(&contents_texture_)));
   *texture_mailbox =